vendor/llvm/llvm-trunk-r366426

1 files changed, 85 insertions, 0 deletions

diff --git a/lib/Transforms/Scalar/LowerWidenableCondition.cpp b/lib/Transforms/Scalar/LowerWidenableCondition.cpp
new file mode 100644
index 000000000000..5342f2ddcb6b
--- /dev/null
+++ b/lib/Transforms/Scalar/LowerWidenableCondition.cpp
@@ -0,0 +1,85 @@
+//===- LowerWidenableCondition.cpp - Lower the guard intrinsic ---------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+//
+// This pass lowers the llvm.widenable.condition intrinsic to default value
+// which is i1 true.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Transforms/Scalar/LowerWidenableCondition.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Analysis/GuardUtils.h"
+#include "llvm/IR/BasicBlock.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/Intrinsics.h"
+#include "llvm/IR/Module.h"
+#include "llvm/IR/PatternMatch.h"
+#include "llvm/Pass.h"
+#include "llvm/Transforms/Scalar.h"
+#include "llvm/Transforms/Utils/GuardUtils.h"
+
+using namespace llvm;
+
+namespace {
+struct LowerWidenableConditionLegacyPass : public FunctionPass {
+  static char ID;
+  LowerWidenableConditionLegacyPass() : FunctionPass(ID) {
+    initializeLowerWidenableConditionLegacyPassPass(
+        *PassRegistry::getPassRegistry());
+  }
+
+  bool runOnFunction(Function &F) override;
+};
+}
+
+static bool lowerWidenableCondition(Function &F) {
+  // Check if we can cheaply rule out the possibility of not having any work to
+  // do.
+  auto *WCDecl = F.getParent()->getFunction(
+      Intrinsic::getName(Intrinsic::experimental_widenable_condition));
+  if (!WCDecl || WCDecl->use_empty())
+    return false;
+
+  using namespace llvm::PatternMatch;
+  SmallVector<CallInst *, 8> ToLower;
+  for (auto &I : instructions(F))
+    if (match(&I, m_Intrinsic<Intrinsic::experimental_widenable_condition>()))
+      ToLower.push_back(cast<CallInst>(&I));
+
+  if (ToLower.empty())
+    return false;
+
+  for (auto *CI : ToLower) {
+    CI->replaceAllUsesWith(ConstantInt::getTrue(CI->getContext()));
+    CI->eraseFromParent();
+  }
+  return true;
+}
+
+bool LowerWidenableConditionLegacyPass::runOnFunction(Function &F) {
+  return lowerWidenableCondition(F);
+}
+
+char LowerWidenableConditionLegacyPass::ID = 0;
+INITIALIZE_PASS(LowerWidenableConditionLegacyPass, "lower-widenable-condition",
+                "Lower the widenable condition to default true value", false,
+                false)
+
+Pass *llvm::createLowerWidenableConditionPass() {
+  return new LowerWidenableConditionLegacyPass();
+}
+
+PreservedAnalyses LowerWidenableConditionPass::run(Function &F,
+                                               FunctionAnalysisManager &AM) {
+  if (lowerWidenableCondition(F))
+    return PreservedAnalyses::none();
+
+  return PreservedAnalyses::all();
+}